Mig welding stainless steel.

[Schnellboot]

Hello to all.

Today I tried my first ever stainless steel welds with the Millermatic Passport.
Wire used was 0,030" 308 LSI and shielding gas was 98% Argon/ 2% CO2. Layed a few beads on some scrap 304 tubing, 0,10" thick I have. I followed the chart settings for tri-mix and set the machine in stainless mode DCEP.
To my surprise I had a lot of spatter. I have no option on using tri-mix because it is not available here.
Checking the Miller resources I see that for short circuit it is recomended tri-mix or 75% Argon/ 25% CO2 and 98% Argon/ 2% CO2 for spray transfer only.

I have the posibility to return the 98/2 bottle of gas, and get a 75/25 one.
What do you think? Will I be able to get better results with 75/25 in stainless steel than I did?

I have had great results with steel wire and CO2 only, so I suspect this spatter I am getting with SS may be due to unsuitable gas blend for the task.

Your input will be greatly appreciated. Thanks!

Regards:

Jerónimo.

[aametalmaster]

I use 75/25 for my SS. When i worked in the shop we used tri mix but the boss payed for it. I don't do enough big jobs to justify another bottle but tri mix would be the proper textbook gas...Bob

[Schnellboot]

I use 75/25 for my SS. When i worked in the shop we used tri mix but the boss payed for it. I don't do enough big jobs to justify another bottle but tri mix would be the proper textbook gas...Bob

Bob, how much spatter do you get with 75/25? I placed a clean 304 sheet piece near the test beads and spater ruined its finish completly. I´m starting to believe that SS is a truly different breed of cat

Thank´s!

Regards:

Jerónimo.

[aametalmaster]

I get some splatter. The best thing to do is cover up what you don't want splatter on just leave the seam showing. Let the ding b a l l s connect to a piece of scrap metal...Bob

[dhlsufan]

Hello to all.

Today I tried my first ever stainless steel welds with the Millermatic Passport.
Wire used was 0,030" 308 LSI and shielding gas was 98% Argon/ 2% CO2. Layed a few beads on some scrap 304 tubing, 0,10" thick I have. I followed the chart settings for tri-mix and set the machine in stainless mode DCEP.
To my surprise I had a lot of spatter. I have no option on using tri-mix because it is not available here.
Checking the Miller resources I see that for short circuit it is recomended tri-mix or 75% Argon/ 25% CO2 and 98% Argon/ 2% CO2 for spray transfer only.

I have the posibility to return the 98/2 bottle of gas, and get a 75/25 one.
What do you think? Will I be able to get better results with 75/25 in stainless steel than I did?

I have had great results with steel wire and CO2 only, so I suspect this spatter I am getting with SS may be due to unsuitable gas blend for the task.

Your input will be greatly appreciated. Thanks!

Regards:

Jerónimo.

I have MIG welded SS for about 10 years on 16ga 304. At the shop we use a mixture of 80/20. At home I use 75/25, and can tell little difference in the amount of splatter. We could get a roll of wire in that may cause more splatter than what was desired, then it would changeon the next roll. I don't know if you are pulling or pushing your weld, but we always pulled ours with good results. You may also want to try nozzle spray on the area your getting the splatter it should clean up pretty good.

Maybe this will help

Darrell

[FusionKing]

Have you tried 100% CO2??

[Schnellboot]

I have MIG welded SS for about 10 years on 16ga 304. At the shop we use a mixture of 80/20. At home I use 75/25, and can tell little difference in the amount of splatter. We could get a roll of wire in that may cause more splatter than what was desired, then it would changeon the next roll. I don't know if you are pulling or pushing your weld, but we always pulled ours with good results. You may also want to try nozzle spray on the area your getting the splatter it should clean up pretty good.

Maybe this will help

Darrell

Darrell, today the guy from the gas rental came to see the problem in person. I showed him the regular steel wire with CO2 and then with the argon/CO2 mix. He did not ask for further test with the SS wire since he said they suspected the cylinder could contamined, he took it for inspection.

I tryied both, pulling and pushing and sparks where there in both cases. Maybe I am accustomed to a "too good" arc of the Passport with CO2?
I have always been told that regular migs with no special inductances where very sparky with CO2, thus I expected less spatter with Agron/CO2 mixes on regular steel wire.
The nozzle spray is a sound idea.
Anyway, I ended doing it with tig, but I am really slow with it. Whats more, my CST is not very easy for me on 18 gauge.

Thank´s!

Regards:

Jerónimo.

[GNLWelder]

Stainless Steel weld

I've use SS wire when welding a hardox plate on top of CS plate they both wear about the same in the caol mine world. With 75/25 or stright CO2 spater is about the same. pulling dose seem to do a little better for me. I also use a spray makes the spater come off better.

[Schnellboot]

Have you tried 100% CO2??

Yes, I works very well form the standpoint of less spatter. The seam obviously gets affected by the active gas, and ends up covered with a black oxide scale.
Even when doing lots of spatter, the gas mix left very clean beads, somewhat bulky for a lot of final grinding.
Since I am building some all SS tables, the only way I could do with the mig without damaging the finish was to cover all exposed surfaces other than the weld joint. That seemed to me more time consuming than to tig all the work.
I am using the 308 lsi wire for tig filler rod and it works very well. I soon discoverd however that the mig wire hung form the ceiling and touching the work can get pretty hot when it touches the tungsten tip, it tenaciously adderes to the tunsten tip, and when orange red in color, cuts through gloves and skin like a hot knife trough butter. OUCH!

Regards:

Jerónimo.

[CarbedNotch]

I use tri-mix gas with mm140 ER308L .025 wire. Never any spatter only black smoke.